Allan,
aside from collimation, you need to ensure you get the mirror distances spot on else you'll have major curvature.
No sure of the exact distances of an RC10 as I have an RC8, but others will know. Else PM LucasB as he ripped his RC10 down plenty of times and know's the answer.
You'll want to platesolve an image to verify the result. Here's a link with some info, and there are plenty more online
https://www.cloudynights.com/topic/4...irror-spacing/
I have a Tak scope, but prefer to use a Howie Glatter Laser Collimator with Concentric rings.
Good luck.
Paul